Carb Jetting/Tuning For Dummies.

Mini Dirt Bikes & Pit Bikes Forum

Help Support Mini Dirt Bikes & Pit Bikes Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

wogtaz ryder

Well-Known Member
Joined
Aug 27, 2007
Messages
4,869
Reaction score
65
Location
brisvegas
A very nice guide that comes with the Purchase of a Pitster .

Its the most easy to understand guide i have seen for tuning a Carby , if you dont understand after this , your stupid.:cool:

Conveniently fit on 1 page . Print it out and take it to your bike!


Setup_jettingmadesimple.jpg



Here is some pretty graphs and things that will teach you more about tuning.
Smaller_PWK_highlow_speed_animation.gif

graph.jpg

Davids_Jetting.jpg
 
Last edited:
It wasn't working for me? Came up with a little white box with a red X in it. So I posted it again and now I can see it.
 
great guide is it for molkt 26mm carb. the ones they stick on stomps
 
It looks like they are using a molkt carby.

But its the same concept for most carbies.
 
Added some nice graphs and things to the first post .

Shows alot better how a carby works
 
I have a new atomik with a 140 yx been ridden for about 2 hours, It is spluttering and coughing and backfiring occasionally, and sometimes sounds like something is happening in the carbi. When i give it some revs to get up a small hill it dies on me and sound really rough. I moved the air fuel screw to try and fix, I've read to screw between 1.5 and 2 turns out, is this 1.5 whole revolutions?? because I have done this and still it inst running right, and it seems to be getting very hot.
I am very new to this what should i do??
 
ok, the 1.5 turns is just a guide to know that you have the pilot jet size near perfect.. and its 1.5 - 2 turns from screwing the fuel screw all the way in and winding it out..
and the fuel screw will only effect it from idle - 1/4 of throttle..

so pilot and fuel screw for idle to 1/4 throttle
slide needle for 1/4 to 3/4 throttle
and main jet 3/4 to full throttle

running hot is a good indication that it is running lean, but before i touched the carby i would be checking the valve clearance.... .003 tho on the inlet .004 thou on the exhaust..

if you adjust the valves and still find there is a stumble in the rev range then the slide needle will probly need raising/lowering by 1 notch at a time.. if the problem gets worse as you raise/lower it then start going the other way..

IE: moving the clip lower on the needle raises the needle and moving the clip higher lowers it..
lower for rich and higher for lean...

if you get to a stage where you have the carby apart.. let us know what jets are installed..

another good thing to try is doing plug chops.. as seen in the first image above...
 
Last edited:

Latest posts

Back
Top